This study seeks to investigate the existence of ethnic differences in birth weight and cesarean deliveries amongst the ethnic groups in Port Harcourt, Nigeria. The study was a retrospective review research. University of Port Harcourt teaching Hospital, Port Harcourt between 2003 and August 2008. The study was a retrospective review research involving a dataset of 1287 (Ibo n = 241, Ikwerre n = 316, Kalabari n = 322, Ogoni n = 200 and Yoruba n =208) culled from over 3560 live singleton births maternity records covering deliveries for five years (2003 - 2008) at the University of Port Harcourt Teaching Hospital; Port Harcourt, Nigeria. The data obtained were analyzed using SPSS statistics software 2008 and the level of significance used was P < 0.05. Student T- test, One-way analysis of variances, Correlation analysis and Pearson chi square. There are significant differences P <-0.001 in the mean birth weights of the five ethnic groups. The prevalence of cesarean deliveries among the ethnic group was significantly associated with the Ibo ethnic group ( Ibo 12.45%, Ikwerre 11.07%, Kalabari 9.94%, Ogoni 7.50% and Yoruba 6.73%: X² = 12.25, df = 2, P = 0.003). The study revealed that the Ibo ethnic group has higher birth weight which may be the predisposing factor to higher percentage of Cesarean deliveries.